Coating composition forming wear-resistant coat and article covered with the coat

Abstract

A coating composition forming a abrasion resistant coating comprising (A) an ultraviolet-curable silicone prepared by chemically modifying particulate colloidal silica with a specific silane compound, (B) a monomer mixture comprising a (meth)acrylate having a specific isocyanate skeleton and a urethane poly(meth)acrylate having an alicyclic skeleton, and (C) a photo-polymerization initiator. By using a urethane poly(meth)acrylate having an alicyclic skeleton as part of the component (B) and the component (A) having an enhanced reactivity of chemical modification, the compatibility of the component (A) with the component (B) is improved to give a cured coating with excellent wear resistance, weather resistance and durability.

What is claimed is:  
     
       1. A abrasion resistant coating composition comprising: 
       (A) 1-50 parts by weight (as solids) of an ultraviolet-curable silicone prepared by chemically modifying 40-90% by weight (as solids) of particulate colloidal silica (a-1) with 10-60% by weight (as solids) of a radical polymerizable silane compound or a hydrolysis product thereof (a-2) represented by the following Formula (I),                    
        (where X represents CH 2 ═CH—COO—, CH 2 C(CH 3 )—COO—, or CH 2 ═CH—; R 1  is an alkylene group with 0-8 carbons; R 2  and R 3  are alkyl groups with 1-8 carbons; a is a positive integer of 1-3; b is a positive integer of 0-2; and a+b is a positive integer of 1-3);  
       (B) 45-95 parts by weight of a monomer mixture comprising 30-90 parts by weight of a tris[(meth)acryloyloxy alkyl]isocyanurate(b-1) represented by the following Formula (II),                    
        (where X 1 , X 2  and X 3  are each either an acryloyl group or a methacryloyl group, R 4 , R 5  and R 6  represent an oxyalkylene group or polyoxyalkylene group) and  
       10-70 parts by weight of a urethane poly(meth)acrylate (b-2) having an alicyclic skeleton along with at least two (meth)acryloyloxy groups in the molecule (wherein the total amount of components (b-1) and (b-2) is 100 parts by weight); and  
       (C) 0.01-5 parts by weight of a photo-polymerization initiator (where the total amount of components (A)-(C) is 100 parts by weight).  
     
     
       2. A coating composition as set forth in claim  1 , further comprising 3-10 parts by weight of (D) an ultraviolet absorber and 0.05-2 parts by weight of (E) a hindered amine photo-stabilizer per 100 parts by weight of the coating composition as set forth in claim  1 . 
     
     
       3. A coating composition as set forth in claim  2  in which the ultraviolet absorber is at least one selected from 2-(2-hydroxy-5-t-butylphenyl) benzotriazole, 2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole, and bis(2,4-dimethylphenyl)-(2-hydroxy-4-(3-myristyloxy-2-hydroxypropyloxy)phenyl)triazine. 
     
     
       4. A coating composition as set forth in claim  2 , wherein the hindered amine photo-stabilizer is at least one selected from bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate. 
     
     
       5. A coating composition as set forth in claim  1 , in which the urethane poly(meth)acrylate (b-2) having an alicyclic skeleton is represented by the following General Formula (III),                    
       (wherein X 4  and X 5  represent acryloyloxy or methacryloyloxy; R 7  and R 8  represent alkyleneoxy or polyalkyleneoxy. 
     
     
       6. A coating composition as set forth in claim  1 , in which the tris[meth]acryloyloxyl]isocyanurate (b-1) is at least one selected from tris(acryloyloxyethyl)isocyanurate, and tris(methacryloyloxyethyl)isocyanurate. 
     
     
       7. A coating composition as set forth in claim  1 , in which the urethane poly(meth)acrylate (b-2) having an alicyclic skeleton is an adduct of iisophorone isocyanate with at least one selected from 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate. 
     
     
       8. A coating composition as set forth in claim  7 , in which the urethane poly(meth)acrylate (b-2) having an alicyclic skeleton is prepared by addition reaction of 2-2.5 moles of a hydroxyalkyl(meth)acrylate to 1 mole of isophorone diisocyanate. 
     
     
       9. A coating composition as set forth in claim  1 , in which the component (B) is a monomer mixture comprising: 30-70 parts by weight of a tris[(meth)acryloyloxyalkyl]isocyanurate (b-1) represented by the following Formula (II),                    
       (where X 1 , X 2  and X 3  are each either an acryloyl group or a methacryloyl group; R 4 , R 5  and R 6  are oxyalkylene or polyoxyalkylene); 10-50 parts by weight of a urethane poly(meth)acrylate (b-2) having an alicyclic skeleton along with at least two (meth)acryloyloxy groups in the molecule; and 2-20 parts by weight of an alkylene glycol di(meth)acrylate (b-3) represented by the following General Formula (V), 
       
         
           X 10 —O—R 12 —O—X 9   (V)  
         
       
       (where R 12  is a branched or linear hydrocarbon group with 4-12 carbons; X 9  and X 10  are acryloyl or methacryloyl); wherein the total of the components (b-1), (b-2), and (b-3) amounts to 100 parts by weight. 
     
     
       10. A coating composition as set forth in claim  1 , in which the photopolymerization initiator, component (C), is used in a combination of 2,4,6-trimethylbenzoyldiphenylphosphine oxide and methylphenyl glyoxylate. 
     
     
       11. A coating composition as set forth in claim  1 , comprising: 
       (A) 1-50 parts by weight (as solids) of an ultraviolet-curable silicone prepared by chemically modifying 40-90% by weight (as solid) of particulate colloidal silica (a-1) with 10-60% by weight (as solids) of a radical polymerizable silane compound or hydrolysis product thereof (a-2), represented by the following General Formula (I),                    
        (where X represents CH 2 ═CH—COO—, CH 2 C(CH 3 )—COO, CH 2 ═CH—; R 1  is an alkylene group with 0-8 carbons; R 2  and R 3  are alkyl groups with 1-8 carbons; a is a positive integer of 1-3; b is a positive integer of 0-2; and a+b is a positive integer of 1-3);  
       (B) 45-95 parts by weight of a monomer mixture comprising 30-90 parts by weight of a tris[(meth)acryloyloxyalkyl]isocyanurate (b-1) represented by the following Formula (II),                    
        (where X 1 , X 2  and X 3  are each either an acryloyl group or a methacryloyl group; R 4 , R 5  and R 6  represent an oxyalkylene group or polyoxyalkylene group), and  
       10-70 parts by weight of a urethane poly(meth)acrylate (b-2) having an alicyclic skeleton along with at least two (meth)acryloyloxy groups in one molecule (wherein the total amount of components (b-1) and (b-2) is 100 parts by weight);  
       (C) 0.01-5 parts by weight of a photo-polymerization initiator (where the total amount of components (A)-(C) is 100 parts by weight);  
       (D) 3-10 parts by weight of an ultraviolet absorber per 100 parts by weight of the total amount of components (A)-(C);  
       (E) 0.05-2 parts by weight of a hindered photo-stabilizer per 100 parts by weight for the total amount of components (A)-(C); and  
       (F) 100-500 parts by weight of an organic solvent formulated per 100 parts by weight of the total amount of components (A)-(C).  
     
     
       12. A coating composition as set forth in claim  11 , in which the organic solvent (F) comprises a combination of 20-50% by weight of an alcoholic organic solvent (f-1), 20-50% by weight of an acetate ester type organic solvent (f-2), and 5-30% by weight of an alkyleneoxyalkyl alcohol type organic solvent (f-3). 
     
     
       13. A coating composition as set forth in claim  11 , wherein the organic solvent (F) comprises a combination of at least one (f-1) selected from isobutanol and n-butanol, at least one (f-2) selected from n-butyl acetate and isobutyl acetate, and at least one (f-3) selected from 3-methoxy-1-propanol, 3-methoxy-2-propanol, 3-methoxy-1-butanol and 3-methoxy-2-butanol. 
     
     
       14. A abrasion resistant coated article obtained by coating a clear thermoplastic substrate with a cured coating of a coating composition as set forth in claim  1 . 
     
     
       15. A abrasion resistant coated article as set forth in claim  14 , in which the clear thermoplastic substrate is polycarbonate.